"page-break-after: avoid", orphans and widows are not supported by Readium

I'd like that a future upgrade of Readium will add support for "page-break-after: avoid", "orphans" and "widows" css properties. Those ones belong to css 2.1 (and ADE 3 and lower have support for them) so I think that with more reason should be implemented for Readium and epub3.
Thank you very much for your attention.